LB7 Tow Build compound turbo/injector questions plus future build.

BudWorx

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Nov 29, 2025
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Sorry if this is in the wrong spot but i've been searching the forums for 3 days and i haven't really gotten anywhere. I need input from the all the pros on here lol. I'm about to start my hunt for a 2002 lb7 to turn into tow rig so i can stop tearing up my half ton. So the plan is once i find a truck, i'm going to get the trans built then i am looking to do a full refresh on the fuel system. New Injectors, lines, cp3, lift pump, anything else that may be recommended? Also will be upgrading the radiator and intercooler (recommendations welcome). I want to do a compound turbo on this rig. Will do fresh manifolds and up-pipes. This truck will have ONE tune only and its going to be the tow tune. What is a reasonable power level for a set off towing compounds. Is 400hp unreasonable? I have no plans on building the bottom end unless i blow the motor which i'm not trying to do. Also how would a Cheetah 63 fit into what im asking here mainly because im sure the truck will need a turbo refresh? My goal is a solid second truck to handle all of my towing needs. Ah lastly what size injectors to match my desired power goals?
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Do not upgrade the stock rad. There is no reliable one out there that wont leak after a while.

400-450hp is a good number to shoot for and not have to get extensively into the cooling system. 475 with a 1.1 t4 exhaust housing as a compound would work extremely well for you. Dont change the stock turbo. 500hp is attainable too depending on the summer temps you see

I’d run 60% or 100% over injectors to keep pulse width low.
 

BudWorx

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Nov 29, 2025
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Louisiana
Do not upgrade the stock rad. There is no reliable one out there that wont leak after a while.

400-450hp is a good number to shoot for and not have to get extensively into the cooling system. 475 with a 1.1 t4 exhaust housing as a compound would work extremely well for you. Dont change the stock turbo. 500hp is attainable too depending on the summer temps you see

I’d run 60% or 100% over injectors to keep pulse width low.
So that would be a no on a mishimoto radiator? Heck that's a little bigger injector than i expected but i understand keeping the pulse width low. Any advantage to a billet wheel 475 on my application? Also are there any twin kits that will tie into an air box such as the s&b? I'd like to run a donaldson powercore filter.
 

2004LB7

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Dec 15, 2010
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I agree with James. The stock turbo can push 500HP. But that is right at it's limit. But 400-450 is easy to do. No need for compounds.

I always found my LB7 ran cooler then my LLY or LMM. Something about how they breath better with less obstructions. I even ran a few seasons with the fan removed because I wanted more heat in the engine. It did finally overheat in the summer when it was really hot out. With the fan it pulled whatever I put behind it with no overheating issues with the 450HP tune as my tow/DD tune

Transmission build is definitely recommended for tuned trucks that want to tow much. So go for that. But maybe skip the compounds and radiator until you have some miles on it and see how it really does

As for injectors, I think you can go either way with stock sized or oversized. Definitely get SAC injectors if you do change them out. I'd probably do 40% if I was doing 400-450HP. Easier to tune and get running smoothly. But 60-100 does over a nice benefit of a short PW that can help keep the cylinder pressure down and increase the life of the pistons and crank.

Are you looking to tune this yourself or do you already have someone in mine? Because most in the US are not doing this type of tuning anymore and it might make sense to do it yourself so you can maintain the tunes for as long as you have the truck
 

BudWorx

New member
Nov 29, 2025
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Louisiana
I agree with James. The stock turbo can push 500HP. But that is right at it's limit. But 400-450 is easy to do. No need for compounds.

I always found my LB7 ran cooler then my LLY or LMM. Something about how they breath better with less obstructions. I even ran a few seasons with the fan removed because I wanted more heat in the engine. It did finally overheat in the summer when it was really hot out. With the fan it pulled whatever I put behind it with no overheating issues with the 450HP tune as my tow/DD tune

Transmission build is definitely recommended for tuned trucks that want to tow much. So go for that. But maybe skip the compounds and radiator until you have some miles on it and see how it really does

As for injectors, I think you can go either way with stock sized or oversized. Definitely get SAC injectors if you do change them out. I'd probably do 40% if I was doing 400-450HP. Easier to tune and get running smoothly. But 60-100 does over a nice benefit of a short PW that can help keep the cylinder pressure down and increase the life of the pistons and crank.

Are you looking to tune this yourself or do you already have someone in mine? Because most in the US are not doing this type of tuning anymore and it might make sense to do it yourself so you can maintain the tunes for as long as you have the truck
I did read alot about using the SAC injectors so that's definitely happening. As for tuning my trans guy has a tuner he uses that i'm hoping can do it. If not i guess ill have to get learning because i don't think my main guy id use can touch it. How does the lb7 compare to the lbz with a tow tune in the 400-450 range? I had an lbz for along time and sold it to get an f250 that promptly ate a cp4 so i regret that choice to this day lol. I'm trying to avoid having a turd of a truck, with that said i'm not trying to make a rocket ship either. I dont want to cook the motor on a hot tow tune with just the factory charger.
 

2004LB7

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Dec 15, 2010
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LB7 and LBZ will be very similar. LB7 is a little easier to tune. But LBZ can be refined a little better. But very comparable

The LB7 has better pistons and the LBZ has better rods. At 400-450HP your not stressing either very much, as long as you are running a good tune. The larger injectors help with this too. One thing to keep in mind is the LB7 is going to be several years older and the electronics like the FICM might fail on you. The LBZ doesn't use an independent FICM and seems to be slightly more reliable. The LBZ also comes with some updates like the 6 speed transmission, externally accessable injectors and higher HP from the factory